.bgc-red {
    background: red;
    height: 200px;
}

.bgc-blue {
    background: blue;
    height: 200px;
}

.bgc-green {
    background: green;
    height: 200px;
}

.clearfix::after {
    content: "";
    display: block;
    height: 0;
    clear: both;
    visibility: hidden;
}

.clearfix {
    *zoom: 1;
}

.mask-background {
    background-color: rgba(red, green, blue, 1);
}